The infrastructure that makes up our world is built to withstand a certain range of weather. Engineers work with a “return period” when designing the bridges we drive across, the sewers that keep streets from flooding, and the electricity grids we depend on. They must ask: how strong can a storm be, how hot can a summer get, before this structure fails? The entire design process assumes a climate that behaves within expected bounds.
Our bodies are not so different. Human physiology evolved under a fairly narrow range of temperatures, humidity, and air quality. We don’t usually think of hearts…
